His vote (assuming the other 5 conservatives agree) would make a per curiam possible, although I don't see them making a straight up call on the merits without oral argument.
Based on composition, I think it is likely Roberts will vote with the other conservatives. And I see him writing a narrowly tailored opinion. Any mildly competent chief justice knows how it works. They vote with the majority if it is going to pass anyway. Then they get to write the opinion if they have a hankering to.
It is rare that the chief justice votes in the minority unless it is some decision they just absolutely abhor.